Case-hardening apparatus.



A. W. MAGHLET. CASE HARDENING APPARATUS. APPLICATION FILED MAY 17, 1906.

m Mm H m LM m m tw W m .m m M e 3 M Q N .N m m m 9 8 N m 1 o H m s I 5 vA. W. MAOHLET. CASE HARDENING APPARATUS. APPLICATION FILED MAY 17, 1906.

Patented Jan. 2, 1912.

2 SHEETS-SHEET 2.

//V 1/5 /1/ TOR Iiil WITNESSES:

ATTORNEY I the flames, and then ADOLPH 'W. MACHLET, OF ELIZABETH, NEWJERSEY.

CASE-HARDENING APPARATUS. J

Specification of Letters Patent.

Application filed May 17, 1906. Serial No. 317,315.,

To all whom it may concern:

Be it known that I, ADoLPH W. MACHLET, a citizen of the United States,residing in Elizabeth, in the county of Union and State of New Jersey,have inventedcertain new and useful Improvements in Case-HardeningApparatus, of which the following is aspecification.

This invention relates to chemically treating articleswhile heated andespecially to case-hardening steel or iron articles inbulk.

In my co-pending application No. 244,244, filed February 4, 1905,(Patent No. 822,460, dated June 5, 1906,) is set forth a manner ofcase-hardening by inc'losing articles in a retort, and both heating androtating the retort While a current of carburizing gas circulatestherethrough.

The obj ects of the present invention are to simplify and reduce thecost of the apparatus and the operation and to adapt the. same forcertain kinds of work.

According articles are placed chamber of an oven directly in the flameand heated directly by the flames are extinguished, and the oven isfilled with oarburizing gas, which cements the articles by means oftheir ownretained heat; a gentle agitation of the articles throughoutthe heating and carburizing operations. This agitation is preferablyeffected by means of a revolving barrel mounted within the oven andcontaining one or more cylindrical rolling shells which hold thearticles; both the barrel and the shells being open to permit freecirculation of carburizing gas therethrough. The barrel is provided witha lid or closure, through which the shells may be removed; and the ovenpreferably has a lid in the form of a removable top to afford access tothe barrel. The walls of the oven are greatly thickened for the purposeof retaining heat,thus delaying the cooling of the articles suflicientlyto enable them to be substantially cemented by their retainedIheat, orbythe heat retained in the oven. The lid of the oven is provided withone or more capacious vents for the escape of products of combustionduring the heating of the articles, and these vents are provided withclosures, whereby they may be closed during the subsequent ('arlmrizingoperation; and the oven is also provided with a constricted regulatablevent for controlling the flow of carburizing gas through to the presentinvention, the

being maintained 1 preferably introduced into the oven through the samepipe which feedslthe burners; and means are providedfor diluting thecarburizing gas by means of an inert gas, such as ammonia. Y

1 Other objects, features and advantages will hereinafter appear.

In the accompanying drawings, Figure 1 is a vertical longitudinalsection of an apparatus for case-hardening according to the presentinvention. Fig. 2 is a plan of a re-,

volving barrel or cage showing particularly the hinged closure of thebarrel through which the shells may be inserted and removed. Fig. 3 isan elevation of one end of the apparatus. Fig. 4 is a transverse sectionof the apparatus.

The even comprises walls 3, 4, bottom or base wall 5, and top wall orcover 6. These walls, which are made of refractory material, are greatlythickened in proportion to the capacity of the oven, so that they retainheat, thereby to delay the cooling of the articles, and hence prolongthecementing operation until a substantial-shell is formed upon thecontained articles. The walls rest upon an iron base plate 7, supportedupon legs 8. iron boxing-9 confines the side and end walls. The lid 6,which is very heavy and rests upon the top edges of the side and endwalls, is lifted off when desired by means of chains 10, to give accessto the interior of the oven. In the 11, which are open during theoperation of heating the oven, and may be closed by.

the oven. The carburizing gas is end walls 1, 2, sidelid 6 are providedcapacious vents Patented Jan. 2,1912.

conical plugs 12 during the subsequent filling of the oven withcarburizing gas.

Gas or other fuel is supplied to the oven through a pipe 13 controlledby a valve 14;

and air is supplied through a pipe 15 controlled by a valve 16; the airbeing preferably supplied under pressure. The mixed air and fuel aredistributed by means of pipes 17, 18, 19 and 20, to burners 21 in thebase of the oven. Preferably the burners are arranged in two series inthe opposite. walls 3, 4, so as to direct the flames along the floor 5of the oven. A thick plate 22 of either iron or refractory material maylie horizontally just above the burners, spaces being left at 23 aroundthe edges of the screen for the passage of flames up into the body ofthe oven, whereby the flames are caused to heat the walls of the ovenvery hot, as well as articles contained therein. The screen also becauseof its great thickness serves as a reservoir of heat effective toprolong the carburizing operation.

Extending through the end walls 1 and 2 of the oven is a horizontalshaft24-, which is preferably made of substantial proportions, so as to avoidcollapse while heated, and the shaft is preferably hollow asillustrated, so as to reduce the weight that must be supported by theheated metal, without substantially weakening the shaft. Secured uponsaid shaft by means of hubs 25, are opposite heads 26, connected by bars27 preferably four in number; the ends of the bars being upset andattached to the heads by means of bolts 28, thus forming a rigidstructure. Hoops 29 are placed at intervals between the heads-andsupported upon the bars 27, thus forming an open work barrel or cage. Asegment 29 of each hoop 1s hinged upon a rod 30 extending along the'barrel; and these hinged form aclosure are locked in by means of slidebolts 31 passing through eyes 32 provided upon the hinges, and en:gaging alining eyes 33 provided upon the barrel heads. 1 Within thebarrel are shown three cylindrical shells or canisters 34 adapted toroll upon the interior sides of the hoops 29 when the barrel is rotated;the shells always tending to find the bottom ofthe barrel, as will beunderstood by reference, to Fig. 4. 'The articles to be case-hardenedare placed within the shells, the latter having coned ends 34, which,though open at 34" for enabling gas to circulate freely therethrough,are still sufficiently closed toretain the articles, with which eachshell may be only partly filled. In order to insert'or remove theshells, the lid 6 of the oven is lifted and swung aside, and the closureof the barrel is unbolted and swung up.

The shaft 24 is revolubly supported by means placed at the exterior ofthe oven where they are not injured by heat. The ends of the shaft 24projects through en'- larged holes 24 in the walls 1 and 2. The lefthand endtof the shaft at Fig.1 turns upon a pair of trundles 35 carriedupon brackets 36 securedto the casing 9 of the furnace. The other end ofthe shaft is provided with a collar 37 supported upon a pair of trundles38, said collar having flanges 39 to engage said trundles, to preventendwise displacement of the shaft. The gradual permanent elongation ofthe shaft due to repeated heating and cooling thereof, is accommodatedby permitting the trundles 35 to engage directly with the shaft itself,since this end of theshaft' may freely slide endwise upon said trundles.The shaft is rosegments which closed positions tated by means of a wormwheel 40- cast upon the collar 37 and operated by a worm of fresh gas.This 41 secured upon a shaft 42, the latter having a sprocket wheel 43connected bya chain 44 to any source of power.

.In operation the lid 6 is lifted, the barrel hoop segments 29 unboltedand raised, and the shells 34 removed, filled with articles andreplaced. Then the segments 29 are closed and locked by the bolts 31.The valves 14 and 16 are then opened and the mixture is ignited at theburners 21, whereupon the lid 6 is replaced, the products of combustionescaping through the vent or vents 11. The barrel is slowly rotated, sothat the articles contained in the shells are kept in constant gentleagitation, whereby they may become evenly heated. -Thehead of the barrelmay be formed with the ends of the shells, so as to retain the latter.The heating proceeds until the articles reach a carburizing heat whichis say above red heat and below the melting point; at-

which time the walls of the oven aswell as the screen 22 are heated toabout the same temperature as the articles. Thereupon the valve 16 isclosed to cut off the air and extinguish the flames at the burners, andthe vents 11 are closed by the plugs 12; and gas may continue to flow inthrough the pipe 13 to immediately fill the oven and carburize thearticles in the shells; this gas being of any suitable quality,carburizing fluid. The rotation of the barrel is continued throughoutthe carburizing operation, so that the articles may be ex- 'posed allover to the atmosphere of gas and ence evenly cemented.

Preferablya constricted vent pipe 46 is fitted'in the lower part of oneof the walls of'the ing gas may pass slowl throu h the oven, thusinsuring the drawiri g ofi of the vitiated gas, and the renewal throughthe pipe 13 vent maybe re lated by a valve 47. The gas escapingt roughthis vent and igniting in the air shows its condition by the color ofits flame. The operator is hence enabled to control the condition and,flowof the gaseous atmosphere in the oven by regulating either valve 47or 14 or both. Owing to the thickness of the heated walls, articles isgreatly delayed, and they are enabled to become cemented to asubstantial depth by means of their own retained heat, or preferably bymeans of the heat retained in' the oven. certain extent, the chemicalaction of the gas thereon ceases; and they may then be removed from theoven or retort and immediately replaced by other articles, so that theoperation of heating may be repeated before the walls of the oven havelost a great amount of heat. In case the cementation does not proceed toa sufiicient depth, they may be allowed to remain in the oven,

rings 45 to' be engaged by as coal gas or any other oven, so thatthecurrent of carburiz- After the articles cool to aof heating the oven.and ammoma may whereupon the flames may be again ex-i tinguished andcarb urizing gas supplied to.

the oven, thus causing the cementation-of the articles to proceed to agreater depth; and this operation may be repeated onthe same articlesuntil they have the required depth of cementation; the agitation thereofbeing continued throughout the repeated heating and carburizingoperations.

Ammonia or other inert gas ma be admitted through a pipe 48 which winsthe pipe 17 and is provided with a valve 49, the latter being closedduring the operation be controlled by said valve 49; or other'means maybe provided for securing asupply of diluted gasto the oven. It will beseen. burning mixture, but also the carburizing gas, with or without itsdilutant are admitted through the burners; but the carburizing gaseither dilutedv or not may be otherwise introduced into the oven.

The invention is of great value in casehardening ordinary wire nails, aswell as other small articles. A-case hardened nail possesses greatadvantage over the ordinary nail in that it has sufiicient strength inproportion to its diameter. In other words the ordinary nail is too weakto stand the pounding necessary. to make a hole in the wood of thediameter of the nail; but by case-hardening the nail this difficulty isovercome. Thenails may be readily casehardened in bulk by the hereindescribed means.

Variations may be resorted to within the scope of the invention, andportions of my improvements may be used without others. 1Having thusdescribed 'my invention, I c aim:

1. The combination of a closed heatinga barrel in said receptacle, andexterior of the receptacle and receptacle, means at'the connected tosaid barrel for revolving the same; said barrel comprising a pair ofheads, a series of hoops between said heads,

, and bars connecting .said heads and supporting said hoops, andcanisters confined in said barrel to be tumbled thereby for the purposespecified.

-. 2. The combination of a closed heating receptacle, 'a barrelcontained in said receptacle, and means at the exterior of thereceptacle and connected to said barrel for revolving the same saidbarrel comprising a pair of heads, a series of hoops between The mixtureof gas that not only the said heads, and bars connecting said heads andsupporting said hoops; each hoop having a section which is hinged togive access to the interior of the barrel.

3.-The combination of a closed heating receptacle,

heating receptacle,

a barrel contained in said receptacle, means at the exterior of thereceptacle and connected to said barrel for revolving the same; saidbarrel "comprising a pair of heads, 'a series of hoops .between saidheads, and bars connecting said heads and supporting said hoops; eachhoop having, a section which is hinged to give access to the interior ofthe, barrel, and releasable means for locking the hoops in closedrelation. A

4. The combination with a closed heating receptacle, of a barrelcontained in said receptacle, a shaft extending through the wall of saidreceptacle, and having supporting means exterior to said receptacle, andmeans for rotating the shaft; said' barrel comprising a pair of headssecured to the shaft, hoops between said heads, and bars connectingsaid. heads and supporting said hoopsya segment of each hoop extendingbetween adjacent bars being hinged, the segment having eyes, andlocln'ng bolts passing through the eyes and releasably engagilngdeyeswhich are provided upon sai ea s.

5. The combination ,of a closed metalheating receptacle, a barrelmounted therein for rotation, and a shell to contain the articles to beheated, said shell lying within said barrel and constructed to roll uponthe in terior of the barrel when the latter is turned.

. 6. The combination of a closed metala barrel mounted therea shell tocontain the in for rotation, and;

- articles to be heated, said shell lying within said barrel andconstructed to roll upon the interior of the barrel when the latter isturned, both said barrel and said shell being open to permit freecirculation of gas therethrough. 7. The combination of a closedmetalheating rece tacle,'means for supplying gas thereto, a arrel withinsaid receptacle,

means at the exterior of said receptacle for supporting and turning saidbarrel, and a plurality of rolling shells contained in said barrel, bothsaid barrel and said shells having openings for the circulation of gastherethrough. 3

8. The combination of a closed metalheating receptacle, means forsupplying gas thereto, a barrel within said receptacle, means at theexterior of said receptacle for supporting and turning said barre1,'anda plurality of rolling shells contained in said barrel, both said barreland said shells having openings for the circulation of gas there-.through; said barrel having an opening through which said shells may beremoved, and a closure for said opening. v

9. The combination of a closed metal-heating receptacle, a shaftextending through opposite wallsthereof, means at the exterior of saidreceptacle for supporting and turning a pair of ing said shaft, shaftwithin said receptacle and comprisheads, hoops intervening between. saidheads and means supporting said hoops, and a cylindrical shell withinsaid barrel and constructed to roll upon said hoops when the barrel isrotated.

10. The combination of a closed metalheating receptacle, a shaftextending through when the barrel is rotated, each of said hoops havinga hinged section to permit removal of said shell, and means beingprovided for locking said sections said shell having openlngs at itsends for the free circulation of.

gas therethrough.

11. The combination of a closed heating receptacle, a barrel mountedtherein and having openings, means for supplying gas to said receptacle,and a cylindrical shell contained in said barrel and constructed to rollwithin the same, said shell havingopenings at its ends for the freecirculation of gas therethrough.

12. The combination of a closed-heating receptacle, a barrel mountedtherein and having openings, means for supplying gas to said receptacle,and a cylindrical shell contained iii said barrel and constructed toroll within the same, said shell having open coned ends,

13. The combination with a heating chamber, of a cylindrical shellwithin said heating chamber and said shell having open coned ends, meansWithin the heating chamber for rolling said shell, and means forsupplying gas to the heating chamber.

14. The combination with a closed-metaL heating chamber provided with arestricted vent, 'and' means for conducting carburizing,

gas thereto, of means contained within the chamber for effectingagitation of the metal articles contained therein, and driving mechanismexterior to the chamber and connected to said agitating means.

15. Theicombination with a closed metalheating chamber provided with arestricted vent, and means for conducting of an open device within thechamber for containing the articles to be heated, and power-driven meansextending from the exterior of the chamber and through the wall thereofto said containing device, for effecting movement of the latter toagitate its contents.

- 16'. The combination with a closed metalheating chamber provided witha restricted vent, and means for conducting gas thereto,

a barrel mounted upon said said oven,

hoops intervening between,

gas thereto,

of an open shell within the chamber, and

power-driven 'mechanis'm including a part extending through the wall ofthe chamber whose walls are formed of refractory material, of burnersfor mixed air and fuel in means for supplying the oven,

after the extinction of flames at the burners,

with a gas capable of chemically acting upon the articles contained inthe oven while they remain heated, and means for agitating the articlesin the oven; the walls of the oven having great thickness for retainingheat so as to maintain theheat of the articles during, the action of thegas thereon.

18. The combination of a closed oven having thick walls. of refractorymaterial, a series of burners in said oven, means for supplying mixedair and fuel to said burners, means for supplying to the oven, after Iextinction of flames at the burners, carburizing as, and means forgently agitating the artlcles within the oven; said oven provided with acapacious vent for the products of combustion, and with a closure forsaid vent.

19. The combination of a closed oven having walls ofrefractory-material, said walls being thickened for the purpose ofretaining heat, a series ofburners in said oven, means for supplying aburning mixture to said burners, and means for passing a slow current ofcarburizing gas through the oven after extinction of the flames at theburners, and power-driven mechanism partly within and partly without theoven, for agitating the articles therein.

20. The combination of a closed heating chamber in the form of an ovenhaving thickened walls of refractory material, ase' ries of burners insaid oven for burning mixed air. and fuel, means for supplyingiron-earburizing gas to said oven after the extinction of the flames atsaid burners, a device within said oven for holding the articles to becarburized, and mechanism for moving said holding device, to agitate thearticles therein; said holding device being open so as to permitcirculation oficarburizing gastherein.

21. The combination of a heating chamber in the'form of an oven providedwith thickened heat-retaining walls, means for creating flames in saidoven and venting the products of combustion therefrom, meansforesupplying iron-carburizing gas to said oven after the extinction ofthe flames therein, an open shell mounted within the'retort,

for containing the articles to be case-hardened, and means including apart extending through the wall of the oven, for effecting slow rotationof said shell.

i and an open rolling 22. The combination in the form of an oven havingalid, means for creating flames insaid retort and then supplyingcarburizing gas extinction of the flames, a barrel mounted in the ovenand having openings for the circulation of gas therethrough, and meansoutside of the oven for both supporting and rotating the barrel.

23. The combination of a heating chamber in the form of an oven, meansfor creating flames in said oven and for causing the ings for thecirculation of gas therethrough, after extinction of the flames, abarrel movably mounted in the oven and having openings for thecirculation of gas therethrough, shell contained in said barrel forholding the articles to be heated 3 said oven provided with a lid.

-a series of burners oven, and means for supplying 24:. The combinationof an oven having a lid, means for creating flames in said oven and forcausing the circulation of carburizing gas therethrough after extinctionof the flames, a barrel mounted in the oven and having openings for thecirculation of gas therethrough, an open rolling shell contained in saidbarrel for holding the articles to be heated, and means outside of theoven for supporting and rotating said barrel; the latter having anopening for the removal of said shell, and a closure for said opening;said oven provided with a capacious vent for the roducts of combustion;and with a closure or said vent.

25. The combination of an oven having a lid in the form of a removabletop, of said oven being thickened to retain heat, for mixed airvand fuelopening into said oven, a revoluble open receiver mounted in said ovenfor holding the articles to be case-hardened or treated, a thick screenbetween said burners and said receiver, flame passages being leftbetween the edges of the screen and the walls of the gas to said ovenafter extinction of flames at said burners; the oven provided with acapacious' vent for the products of combustion and with a closure forsaid vent, andf also with a regulatable constricted vent for regulatingthe passage of gas through the oven.

26. The combination with an oven having means for retaining heat, ofmeans for cre-.

ating flames in said oven and causing them to play upon saidheat-retaining means,

of a heating chamber thereto after the the walls means for causingarticles in the oven to be heated uniformly throughout, means forextinguishing the, flames in the oven, and means operable after theirextinction, for

' subjecting the articles uniformly to the action of gas thereon. v d

27. An apparatus for carburizing iron or steel articles, comprising aheating chamber of refractory material having three separate supplypipes 13, 15 and 48 for air, fuel gas and car urizing gas respectively,and

means for closing the air and fuel gas pipes and opening the carburizinggas pipe to the chamber, and agitating the articles.

28. A furnace in which .is' mounted a barrel revoluble upon an axleprojecting through the walls of the furnace and supported upon trundlesoutside of the furnace, said furnace having a removable cover pro videdwith vent-holes having closures, and means for introducing either gasalone or gas mixed with air; said furnace provided with a re latableconstricted gas-vent.

29. -A urnace in which is mounted a bar'- rel' revoluble upon anaxleprojecting through the walls of the furnace and supported upon trundlesoutside of the furnace, said furnace having a removable cover providedwith vent-holes havingclosures,and means for introducing either gasalone or gas mixed with air; said furnace provided with a regulatableconstricted gas-vent, and having in its bottom a are burners for thegas, said burnerswithin the flame chamber of the furnace.

heat-bed below which 30. The combination with a heating chamber, of abarrel mounted therein for revolution and consisting of heads, tie-rods,hoops, a hollow shaft upon-which the heads are mounted, and a canisterwithin the barrel to contain the articles to be case-hardened.

31. The combination of a heating chamber having meansfor supplyingthereto either fuel gas mixed with air or carburizing gas after theflames are extinguished, av device revolubly mounted in said heatingchamber,

the latter having a removable top, and a clo'sable vent in said top forthe products of combustion, and a regulatable constricted vent in thesidewall of the chamber for the carburizing gas.

slow escape of MACHLET.

ADOLPH W. Witnesses:

SAMUEL R. OGDEN, -PHILIP G. OSTERMAN.

